Gwénaël Jan

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BACKGROUND Propionibacterium freudenreichii is essential as a ripening culture in Swiss-type cheeses and is also considered for its probiotic use. This species exhibits slow growth, low nutritional requirements, and hardiness in many habitats. It belongs to the taxonomic group of dairy propionibacteria, in contrast to the cutaneous species P. acnes. The(More)
BACKGROUND Due to its capacity to produce large amounts of cellulases, Trichoderma reesei is increasingly been researched in various fields of white biotechnology, especially in biofuel production from lignocellulosic biomass. The commercial enzyme mixtures produced at industrial scales are not well characterized, and their proteinaceous components are(More)
The genus Propionibacterium is composed of dairy and cutaneous bacteria which produce short-chain fatty acids (SCFA), mainly propionate and acetate, by fermentation. Here, we show that P. acidipropionici and freudenreichii, two species which can survive in the human intestine, can kill two human colorectal carcinoma cell lines by apoptosis. Propionate and(More)
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a pleiotropic enzyme that is overexpressed in apoptosis and in several human chronic pathologies. Here, we report that the protein accumulates in mitochondria during apoptosis, and induces the pro-apoptotic mitochondrial membrane permeabilization, a decisive event of the intrinsic pathway of apoptosis.(More)
Tolerance to digestive stresses is one of the main factors limiting the use of microorganisms as live probiotic agents. Susceptibility to bile salts and tolerance acquisition in the probiotic strain Propionibacterium freudenreichii SI41 were characterized. We showed that pretreatment with a moderate concentration of bile salts (0.2 g/liter) greatly(More)
The acylation of Mycoplasma gallisepticum membrane proteins was studied by electrophoresis after in vivo labelling with different 14C-fatty acids and by chemical analysis. The immunological properties of these proteins were investigated by Western blotting and crossed immunoelectrophoresis. Among the ca. 200 membrane polypeptides resolved by two-dimensional(More)
The plasma membrane of the avian pathogen Mycoplasma gallisepticum contains about 200 polypeptides including the major lipoprotein pMGA. We have developed a simple and efficient procedure for the purification of three membrane proteins of this wall-less bacterium. Proteins were selectively extracted from isolated plasma membranes with the mild zwitterionic(More)
Dairy propionibacteria are Actinobacteria, mainly isolated from dairy environments. Propionibacterium freudenreichii has been used for a long time as a ripening culture in Swiss-type cheese manufacture, and is more and more considered for its potent probiotic effects. This review summarises the knowledge on the main P. freudenreichii pathways and the main(More)
Probiotics have been the subject of intensive research, mainly focusing on bifidobacteria and lactic acid bacteria. However, there is evidence that dairy propionibacteria also display probiotic properties, which as yet have been underestimated. The aim of this paper is to review recent data which report probiotic characteristics of dairy propionibacteria(More)
Proteomics is a powerful tool that can simultaneously analyze several hundred proteins in complex mixtures, either through the use of high-resolution 2-dimensional gel electrophoresis or by mono- and multi-dimensional liquid chromatography coupled with mass spectrometry. Since the last review in 2005, proteomics has mainly been applied to describe minor(More)